Objective: To observe the changes of vision and visual evoked potentials (VEP) in patients with Leber hereditary optic neuropathy (LHON) before and after gene therapy. Methods: A retrospective cohort study. From December 2017 to October 2018, 35 cases of 70 eyes of m11778G.A/MT-ND4 mutant LHON patients who were diagnosed in the Tongji Hospital of Huazhong University of Science and Technology and received gene therapy were included in the study. There were 30 males (87.71%) and 5 females (12.29%), with the mean age of 23.31±6.72 years. The gene therapy method was intravitreal injection of rAAV2-ND4 (recombinant adeno-associated virus carrying NADH-ubiquinone oxidoreductase subunit 4 gene) into one eye. The eye with poor visual acuity was chosen as the injection eye. If both eyes had the same visual acuity, the right eye was designated as the injection eye. Seventy eyes were divided into the injected eye group and the non-injected eye group, in which were both 35 eyes. The best corrected visual acuity (BCVA) and pattern VEP (PVEP) examinations were performed in the injected eye group and the non-injected eye group before treatment (baseline), 1, 3, and 6 months after injection. Compare the changes of BCVA and PVEP between the injected eye group and the non-injected eye group at baseline, 1 month, 3 months, and 6 months after injection. Independent sample t test, paired sample t test or two independent sample nonparametric test were performed to compare the two groups. Results: Compared with baseline, 1, 3, and 6 months after treatment, the BCVA of the injected eye group (t=3.530, 4.962, 5.281; P=0.001, 0.000, 0.000) and the non-injected eye group (t=3.288, 2.620, 2.252; P=0.002, 0.013, 0.031) increased, and the difference was statistically significant; there was no statistically significant difference between VEP IT (tinjected eye group=-0.158, 1.046, -1.134; Pinjected eye group = 0.875, 0.303, 0.190; tnon-injected eye group=0.773, -0.607, -0.944; Pnon-injected eye group = 0.445, 0.548, 0.352) and VEP A (Zinjected eye group=-0.504, -0.934, -1.065; Pinjected eye group = 0.614, 0.351, 0.287; Znon-injected eye group=-0.521, -0.115, -0.491; Pnon-injected eye group = 0.602, 0.909, 0.623). Conclusion: After gene therapy, the visual acuity of the injected and non-injected eyes of LHON patients improved; PVEP did not change significantly, and remained stable compared with baseline. © 2021 Chinese Medical Association